Instructions: In a glass or ceramic bowl, whisk together egg yolk, salt and mustard. Combine lemon juice and vinegar in a separate bowl, then thoroughly whisk half into the yolk mixture. Start whisking briskly, then add the oil a few drops at a time until liquid seems to thicken and lighten a bit. Continue adding oil in a thin stream; increase oil flow to a constant, thin stream. Once half of oil is in, add remaining lemon juice mixture. Continue whisking until all oil is incorporated. You can also do this quickly and easily in a blender. Leave at room temperature if using immediately or refrigerate for up to 1 week.

Note: Raw eggs can contain salmonella bacteria, which can cause illness in people with compromised immune systems, the young, the elderly, pregnant women and those with chronic illnesses. If the uncooked egg is worrisome, use pasteurized eggs, available at most H-E-B stores.